Thomas,

>I am working with VS2008 SP1 and MM 3.5 to build ASP Websites.
>When I click the ... Button in the Properties window to select the BindingSourceMember for a TextBox on a webpage, then I get the Error "Length cannot be less than zero. Parameter name: length". After the error Messagebox, I get the form to select the database etc., but all the field are empty, so that I can't select anything.
>The ...Button for the BindingSource works correctly.
>
>Pressing the .. Button to generate the ControlID to secure the control, brings up a Microsoft Visual Studio Message Box with the Error message "Length cannot be less than zero. Parameter name: length".
>
>Any ideas how to fix this behaviour?

In both cases, the dialogs are using the connection string stored in your config file to access you database--in the first case to get a list of tables/fields, and in the second case to save the new Control ID to the database. I recommend checking your connection string for errors. Check both the database settings in the web.config and business object app.config files. It sounds like it's more than just an invalid connection string--more like an invalid or improperly formed XML in the file. You may want to copy a web.config from another or brand new Web project just to start with a clean slate.

Best Regards,